Almost 25 holes have been found in the grounds of the Roman fort of Longovicium, near Lanchester, County Durham, The land owner, Nick Greenwell, said damage to the site had been carried out in the last two weeks.

He said: “It is people using metal detectors coming in at night.It is an historic site and whatever that has been taken could be of great value.”

The site, which covers six acres of land, has not been excavated for 40 years, but was once home to 1,000 soldiers and cavalry.

It was on one of the Roman army’s main supply routes from York to Scotland and treasures that have been discovered there in the past include altars to Roman gods.

Mark Harrison, national policing and crime advisor for English Heritage, said local police had been informed and villagers should be aware of the archeological treasure they have on their doorstep.

He said: “By informing people what heritage sites are in their community we have got a chance of protecting those sites and if offences do happen we have got a better chance of catching those offenders. What we are talking about a minority of criminals using sophisticated electronic equipment to steal property that belongs to the land owners, and more importantly, they are stealing the knowledge that belongs to all of us.”